Solar Cell and Solar Panel Qualification Standards: Progress in Establishing a Minimum Baseline for

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Solar Cell and Solar Panel Qualification
Standards Progress in Establishing a Minimum
Baseline for Performance

• Brad Reed
• The Aerospace Corporation
• Presented to
• 2005 IEEE Microelectronics Reliability
• and Qualification Workshop (MRQW)
• Manhattan Beach, CA
• December 6, 2005

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Outline

• Background
• New Solar Cell and Solar Panel Qualification
  Methods
• Path Forward

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Solar Cell Design Process Was Broken

• Problem Identification
• 2.1 Billion in insurance claims, mainly related
  to solar array degradation/failure in 2001
  (Aviation Week and Space Technology, May 19,
  2003)
• Similar government experience
• How to Fix it?
• Develop Data Collection Standards
• Provide Information Dissemination
• Develop Standard Qualification Methodologies

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Multijunction Solar Cells Recent History

• In pursuit of higher efficiencies, III-V
  multi-junction (MJ) solar cells are becoming more
  complex
• Current Products (Technology Readiness Level 5-9)
• 25-28 efficient
• Spectrolab Triple Junction (TJ), Improved Triple
  Junction (ITJ), Ultra Triple Junction (UTJ)
• Emcore Triple Junction (TJ), Advanced Triple
  Junction (ATJ), Advanced Triple Junction with
  Monolithic Bypass Diode (ATJM), Better Triple
  Junction with Monolithic Bypass Diode (BTJM)
• New Products (Technology Readiness Level 3-4)
• 30 efficient XTJ (Spectrolab), ZTJM (Emcore)

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Solar Cell History Technology Evolution
AFRL Testing
NASA Testing
Mil-Stds
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Current Solar Cell Technology Readiness Levels
(TRLs)Projected Qualification at TRL 5,
Characterization at TRL 4
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New Qualification Standards

• Qualification and Quality Requirements for Solar
  Cells, AIAA S-111-2005 (19 pages)
• Qualification and Quality Requirements for Solar
  Panels, AIAA S-112-2005 (15 pages)
• Both AIAA Documents Published September, 2005
• 13 month effort
• 28 reviewers from 14 organizations including
  prime contractors, solar cell/panel
  manufacturers, government customers

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Basis for Sample Size in Tests

• Qualification test sample requirement
• Sample assumed to have a binomial distribution,
  test run at 90 confidence level with less than
  1 defectives (231 samples)
• Characterization test sample requirement
• Sample assumed to have a binomial distribution,
  test run at 90 confidence level with less than
  10 defectives (22 samples)
• - or -
• If industry experience shows that smaller sample
  size yields reliable characterization tests then
  accept industry advice

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Sampling PlanBased on 90 confidence level
Qualification
Characterization
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Summary of Solar Cell Qualification and
Characterization TestsAIAA S-111-2005
Qualification Tests
Characterization Tests
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Summary of Differences between Old and New Solar
Cell Test Protocols

• For future programs
• Qualification now consistent across programs
• Solar cell qualification standard non-tailorable
• Pedigree insight back to original qualification
• Sample sizes increased
• Excludes non value-added tests
• Includes Test as You Fly Tests
• Includes qualification tests (TRL 5)
• Includes characterization tests (TRL 4)
• Includes standardized reporting format

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Summary of Solar Panel Qualification and
Characterization TestsAIAA S-112-2005
Qualification Tests
Characterization Tests
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Summary of Differences between Old and New Solar
Panel Test Protocols

• For future programs
• Qualification now consistent across programs
• Solar panel qualification standard tailorable
• Pedigree insight back to original qualification
• Sample sizes increased
• Excludes non value-added tests
• Includes Test as You Fly Tests
• Includes qualification tests (TRL 5)
• Includes characterization tests (TRL 4)
• Includes standardized reporting format

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Path Forward

• Development of Acceptance Test Requirements
• Solar Cell
• Solar Panel
• ISO Standard
• Combination of AIAA documents with ECSS E-20-08
  Photovoltaic Assemblies and Components
  (November 2004) format

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Summary

• Qualification and Characterization Tests
  Published through AIAA
• Acceptance Tests under Construction
• ISO Standard to be submitted by US developed
  for NASA by The Aerospace Corporation using
  current AIAA documents